The invention relates to a cooling apparatus for the internal combustion engine of a motor vehicle, comprising a cooling-air fan, a radiator assembly and a fan shroud which extends from a fan ring, enclosing the cooling-air fan, as far as the radiator assembly, the radiator assembly projecting laterally beyond the projection of the cooling-air fan, and the projection of the cooling-air fan projecting upward and/or downward beyond the radiator assembly.
Such a cooling apparatus is described, for example, in DE-A 24 39 033 or also in DE-A 34 04 887. As is customary in vehicles with a longitudinally installed engine, the fan is driven by the latter via a V-belt. It covers over a circular surface, of which the vertical position, on account of the drive, is usually unfavorable and can only be selected within narrow limits. For aerodynamic reasons, it is desirable in modern vehicles to have a bonnet which slopes away sharply. In the case of a certain necessary cooling surface, this necessitates a very wide and low radiator assembly.
The radiator assembly projects beyond the projection of the circular surface of the fan at least on one side (in the case of an asymmetrical arrangement), but usually on both sides, and the circular surface, for its part, projects beyond the top edge of the radiator assembly. The fan shroud has to overcome this unfavorable offset flow, which is barely possible on account of the small axial spacing. This results in regions of the radiator assembly which have insufficient flow passing through them, if any at all, and sectors on the cooling-air fan which receive insufficient flow. These regions and sectors can be seen in DE-A 24 39 033.
The consequence is that the cooling system, in certain critical situations (at a standstill in hot climates, where possible still with the air-conditioning system switched on, traveling on inclines under full load, etc.), fails or has to be safeguarded by complex and costly additional precautionary measures (over-dimensioned parts, additional electric fan, temperature-controlled switch-off of additional heat sources, etc.).
The object of the present invention is to improve a cooling apparatus such that, with given dimensioning of the radiator assembly and cooling-air fan, the cooling capacity is increased, with a minimum of structural outlay. Retrofitting in existing vehicles is to be possible.